This is shaping up to be a pretty significant year for the cannabis industry.

Three states – Illinois, Maryland and New Hampshire – have passed medical marijuana laws since January, creating tens of millions of dollars in opportunities for cannabis businesses.

In the past, the industry could thank voters – usually far more sympathetic to the cannabis cause than politicians – for this type of progress. This year, however, state lawmakers are behind the gains, part of a larger trend fueling the industry’s march across the United States as of late.

Since 2010, seven state legislatures have passed laws approving the use of medical marijuana (including Maryland’s very limited and restrictive program), vs. just three previously. By comparison, only two states have passed MMJ laws via ballot measures since 2010 vs. 10 (including Washington DC.) in the decade-plus prior.

Throw in the fact that two existing states (Nevada and Oregon) finally paved the way for regulated dispensaries and a third (Delaware) is moving in that direction as well, and it’s clear state lawmakers have become much more friendly to the MMJ industry.

There’s a good explanation for the trend.

“The reason that more medical marijuana laws have been enacted via state legislatures rather than voter initiatives since 2011 is because it’s currently cheaper to lobby state legislatures than to run ballot initiatives,” said Rob Kampia, executive director of the Marijuana Policy Project, a Washington DC lobbying group that has helped pass many of the most recent MMJ-related laws. “In the first wave of MMJ victories from 1996 to 2000, it was only possible to pass MMJ ballot initiatives in ‘easy’ states like California and Oregon. State legislators and governors simply weren’t ready to take action back then.”

Now, however, state legislators realize that MMJ is politically popular, leading to a second wave of legalization and pro-MMJ laws in general.

Kampia said that his organization could help pass medical marijuana ballot initiatives in “medium-difficulty” states like Arkansas, Idaho, Missouri, North Dakota and Ohio if there was funding to do so (an combined $10 million would be required), but as of right now there isn’t.

“As such, our MMJ work on the state level is focused on state legislatures,” he said.

The trend highlights just how important it is for cannabis businesses in existing MMJ states to create a favorable perception of the industry by following best practices and operating above-board in every respect. Local lawmakers often look to other medical marijuana states when shaping their opinions on MMJ. If they see a well-run system (as Nevada lawmakers did when they visited Arizona recently), they are much more likely to support favorable laws. If they see questionable operations that create problems in local communities, on the other hand, it might be enough to tip the scales against MMJ.

The same trend will likely play out on the recreational side of the equation after the “easy” states legalize marijuana via ballot measures. So it’s equally important for recreational businesses in Colorado and Washington to operate responsibly and pave the way for lawmakers in other states to eventually adopt similar laws.